1. Field of the Invention
This invention relates to aircraft data processing. In particular, the invention relates to data smoothing.
2. Description of Related Art
Military and commercial uses of the Global Positioning System (GPS) have become popular. The commercial use of the GPS for the location of objects has developed many applications to ship navigation, commercial and private aircraft navigation, car navigation, hiking, etc. Military uses of the GPS data are numerous. One military use of the GPS data in aircraft navigation is training air-combat pilots. The GPS data are used to record and playback the position and attitude (as recorded from the avionics systems in the aircraft) of each aircraft during complex air-to-air combat maneuvers.
However, the measurements of aircraft position and dynamic parameters using GPS data in these applications cases still have many problems. First, the GPS data as recorded are usually inaccurate. Typical GPS data have an error of a few hundred meters. This range of error is not acceptable for many data analysis tasks such as post-flight scenario reconstruction. Secondly, in aircraft with high maneuverability such as fighters, the recorded data are very noisy, resulting in inaccurate measurements of aircraft dynamic parameters.
Therefore there is a need in the technology to provide an accurate and efficient method to determine aircraft position and flight dynamic parameters, including attitude, using GPS data.
The present invention is a method and apparatus to determine flight parameters, including attitude, of an aircraft. Data received from a global positioning system (GPS) receiver are converted to position data. The position data are filtered based on a least-squares fitting to generate smoothed position data which provide the flight parameters.